1. Field of the Invention
This invention relates to the field of machines used to form toroids from plastic material, and more specifically to the mandrels which are commonly used in such machines.
2. Description of the Prior Art
There are many prior art devices which form toroids of plastic material such as dough. Some devices use a mandrel to form the hole in the center, in some cases the lump of dough is impaled on a pointed mandrel to form the hole, and in other cases the toroid is formed by two hinged mold halves.
The pertinent art includes the following patents:
______________________________________ Patent No. Inventor Issue Date ______________________________________ 3,031,979 D. T. Thompson 5/1/62 Re. 25,536 D. T. Thompson 3/10/64 3,247,808 D. T. Thompson 4/26/66 3,371,624 D. T. Thompson 3/5/68 3,379,142 B. W. Reiter et al. 4/23/68 3,433,182 M. Thompson 3/18/69 3,491,704 Daniel T. Thompson 1/27/70 3,580,385 Daniel T. Thompson 5/25/71 2,779,298 F. Chwirut et al. 1/29/57 3,080,831 H. Paitchell et al. 3/12/63 3,115,103 G. Huss 12/24/63 3,315,618 E. I. Groff 4/25/67 3,407,754 L. Wichinsky 10/29/68 1,552,430 L. Gendler 9/8/25 1,755,921 L. Gendler 4/22/30 2,584,514 M. Thompson et al. 2/5/52 2,611,329 R. M. Lehman 9/23/52 2,628,578 E. J. Roth 2/17/53 2,666,398 L. Gendler et al. 1/19/54 ______________________________________
The Reiter et al. U.S. Pat. No. 3,379,142 discloses a pair of endless chains spaced vertically one above the other so that the upper run of the lower chain and the lower run of the upper chain run parallel to one another and each carry a half mold for the external shape of bagel. Disposed between the upper and lower molds is a forming mandrel which extends longitudinally between the molds for the length of their horizontal run during which the two mold halves form a complete mold, with the mandrel then turning downward about the sprocket of the lower mold run as the upper mold sections are separated upward and away from the lower mold section. The Rieter apparatus has means for dropping a ball of bagel dough downward by gravity into a lower mold which carries the dough beneath the central mandrel into the region where the upper mold comes downward and forms a complete mold with the lower mold section and with the mandrel enclosed therewithin. The ball of dough is rolled around the mandrel and formed as it progresses longitudinally from one end of the closed mold section to the other end. The first eight claims of this patent specifically set forth the two endless chains and the upper and lower mold sections. Claim 9 of this patent claims only the mandrel which is specifically shown and described in this patent. The mandrel is shown in FIG. 2 and includes the sections 64a, 64b and 64c which are successive forming sections for the bagel and are of successively increasing diameter. This successively increasing diameter of the three forming sections is clearly described in the specification and is set forth in claim 9.
U.S. Pat. No. 3,031,979 to Thompson has been reissued as reissue patent Re. 25,536 and covers apparatus which includes a central mandrel having a sharp point at its free end upon which a lump of bagel dough is impaled to provide the central bagel hole, and the lump is then enclosed in a form which has hinged side walls that are closed inward about the lump to roll the lump along the mandrel and form the finished bagel. The claims of this reissue patent all include a limitation in one form or another which sets forth the impaling of the dough lump upon the central mandrel. U.S. Pat. No. 3,247,808 is a divisional patent derived from the original reissued U.S. Pat. No. 3,031,979, and which covers the method of making a bagel as disclosed in the reissue patent 25,536 just described. The method of course includes the step of impaling the ball of bagel dough on the pointed end of an elongated rod or mandrel.
The 1971 U.S. Pat. to Thompson No. 3,580,385 describes and claims a transport apparatus for conveying lumps of dough to a bagel making machine but does not cover a bagel making machine itself.
The 1970 U.S. Pat. to Thompson No. 3,491,704 illustrates and describes a bagel forming machine having a mold made of a fixed bottom form and a pair of side forms which are moved together to complete a toroid and are opened up to release the formed product. The machine utilizes a strip of bagel dough which is laid in the mold and is then wrapped about a central mandrel by the reaction of the inwardly pivoted sides of the mold as they come together.
The 1969 U.S. Pat. No. 3,433,182 to Meyer Thompson is another apparatus which forms a bagel from a strip of bagel dough, the sequence being shown most clearly in the FIG. 17 of the drawings, while the apparatus is perhaps best seen in FIGS. 12 through 15 of the drawngs. This apparatus is again similar to the just described Thompson U.S. Pat. No. 3,491,704.
The 1968 U.S. Pat. No. to Thompson 3,371,624 deals generally with an apparatus having a two part hinged sleeve mold structure with a mandrel which moves axially within the sleeve.
The 1968 U.S. Pat. No. to Wichinsky 3,407,754 is a very simple apparatus for making bagels which essentially starts with a lump of dough carried on a conveyor under a forming device to convert the lump into an elongated cylindrical strip, which strip is then carried along by the conveyor into a region where the conveyor itself is turned upwards at both sides into a cylindrical shape by means of a tubular sleeve. A central mandrel running through the tubularly formed portion of the conveyor provides a form about which the strip of dough is turned upward and about to form a completed bagel which is discharged at the opposite end of the conveyor after the latter has returned back to its flat shape. All of this is rather clearly illustrated in the single figure of the Wichinsky patent.
The 1967 U.S. Pat. No. to Groff 3,315,618 is a machine for making circular pretzels. The apparatus as disclosed requires the use of elongated cylindrical strips of dough which are draped about a mandrel in inverted U-shape and then have their drooping ends pushed inward and around the mandrel and pressed together to form an annulus.
The 1963 U.S. Pat. No. to Huss 3,115,103 is directed toward the formation of an elongated roll of the hot dog type from an initial dough ball or lump.
The 1963 U.S. Pat. No. to Paitchell 3,080,031 forms bagels from a lump of dough by first impaling the lump on the tip of a cylindrical mandrel, and then rolling the impaled lump upward along the mandrel by means of endless belts to form a finished bagel ring.
The 1957 U.S. Pat. No. to Chwirut 2,779,298 discloses and sets forth in the two claims of the patent an apparatus for extruding a tube of dough and thereafter slicing the tube after extrusion to form rings of dough and to thereafter manipulate the rings so as to form a bagel type torus.
The 1925 Gendler U.S. Pat. No. 1,552,430 discloses an apparatus very much like the Wichinsky U.S. Pat. No. 3,407,754, the basic difference being that Wichinsky shows a former for taking a dough lump and converting it into the strip of dough which is to be formed into the bagel, whereas Gendler does not show such a forming device but starts off with dough strips.
The 1930 patent to Gendler U.S. Pat. No. 1,755,921 again deals with strips of dough which are formed into a bagel.
The 1952 U.S. Pat. No. to Meyer Thompson 2,584,514 is another example of bagel formation starting with a cylindrical strip of dough to form a toroid, and thereafter rolling the formed toroid along a mandrel to further shape it.
The 1952 U.S. Pat. No. to Lehman 2,611,329 discloses a doughnut making machine utilizing an extrusion and reciprocating central disk to provide a cut off action to form a toroid, followed by rolling of the formed toroid along a mandrel to form an external skin for the toroid.
The 1953 U.S. Pat. No. to Roth 2,628,578 discloses a vertically extending mandrel about which is disposed four vertically running belts so that a lump of dough dropped downward between the central mandrel and the belts is carried downward by the belts and spread around the mandrel by the belts and deposited at the bottom on a conveyor which moves it out for further processing.
The 1954 U.S. Pat. No. to Gendler 2,666,298 discloses a bagel making device which first extrudes a lump of dough which is then severed and carried along a conveyor beneath a forming board which spreads the lump out into an elongated cylindrical strip of dough. The cylindrical strip of dough is then deposited on a conveyor in inverted U-shape and carried along and dropped down around a cylindrical mandrel which latter is also surrounded by a moving belt structure to form the dough strip into a continuous bagel shape.
None of these patents discloses a mandrel which is adjustable in both the vertical and horizontal direction and having the ridges as appear on the mandrel of the present invention. None of the prior art devices discloses a means designed to insure that the bagel dough is constantly kept rotating between the time it exits the pressure plate (referred to as a forming board in the discussion of Chwirut above) and the time it encounters the mandrel and is formed into a toroid.
The fact that the bagel or other dough material rolls along the mandrel means that the bagel produced by the mandrel of the present invention is more consistently symmetrical in shape, has a yield of about 99.5% commercially acceptable bagels which is significantly above the percentage yielded by prior art mandrels, and the cross-section of the bagel is more nearly circular than if the bagel were permitted to slide along the surface of the mandrel. If the bagel slides, the hole through the center of the bagel would have a flattened surface rather than circular.